Cathode ray tube washing machines



Feb. 20, 1962 R. H. MORIN 3,021,851

CATHODE RAY TUBE WASHING MACHINES Filed Aug. 29, 1956 2 Sheets-Sheet 1 @y am 1% ATTORA/Ey Feb. 20, 1962 R. H. MORIN CATHODE RAY TUBE WASHING MACHINES 2 Sheets-Sheet 2 Filed Aug. 29, 1956 Unite rl`his invention relates to a bulb Washing machine, and, more particularly, to an automatic in-line cathode ray tube Washing machine.

This invention describes a system for automatically cleaning cathode ray tubes while said tubes are held in a tube hanger, which hanger is supported from a movable chain.

In processing cathode ray tubes, a major cost of the process is the handling of the tube itself. Due to the size of the modern cathode ray tubes, it is desirable from the standpoint of lower operating cost, safety to personnel, and also a lower damage rate, to mechanize the complete operation of the cathode ray tube and reduce to a minimum the handling of the tube. This has been accomplished in all phases in the manufacture of the tube with the exception of the cleaning process. Heretofore, special cleaning machines, consisting of round rotating tables, have been used for cleaning the interior of the cathode ray tube prior to the application of the necessary phosphors. The referred-to rotating machine was necessary, since cleaning of the interior of the tube is done by an acid wash. Spraying the acid within the open neck of a cathode ray tube would be dangerous, unless the tube were positively located by fixed holding devices which held the tube with respect to the nozzles which sprayed the acid. These rotating machines were necessarily large, expensive, and extremely cumbersome due to the large floor area needed. Due also to the necessary positive locking devices needed to hold the tube in the defined relationship with the nozzle, additional personnel were needed to handle the tubes and place them on the machine and then to replace the tubes on a normal system after the cleaning process was over.

ln this invention, an in-line bulb-washing machine is constructed, having a minimum of floor area, and which uses a conventional conveyer system for moving bulbs from cleaning station to cleaning station. This system utilizes a movable conveyer system, which conveyer system consists of a plurality of links forming a continuous chain. Moving means intermittently moves said chain in a single direction at a nonlinear speed, which speed is maximum at a point intermediate the intermittent motions of said chain. Tube holding means adapted to hold a cathode ray tube are attached to and move as said continuous chain moves. Said holding means pass through a plurality of cleaning stations, each having a retractable piston connected at one end to a source of cleaning material and having connected at the other end a nozzle for directing said cleaning material. These pistons are adapted to have the nozzle inserted within said cathode ray tube for cleaning the interior of said tube whenever said tube-holding means stops at a cleaning station. The indexing of the moving chain depends on the physical distance between cleaning stations and the physical distance between the tube-holding means. The indexing is such that, whenever a tube-holding means is located at a cleaning station, the conveyer system is stilled, and further, it is positively locked by means of a plunger which is forced within the links forming said continuous chain.

Further objects and advantages of this invention will be more apparent by referring now to the accompanying drawings wherein:

FIG. l is a top view of a three-station in-line system built in accordance with the teachings of this invention;

States Patent FIG. 2 is a front view of a cleaning station illustrating the relationship between the conveyer system, tube-holding means, and cleaning station;

FIG. 3 illustrates a preferred embodiment the chain during the cleaning cycle;

FIG. 4 illustrates the moving means that drives the chain at a varying speed; and

FIG, 5 is a schematic of the electrical connections for the embodiment illustrated in FIG. l.

Referring now to FlG. l, there is shown an automatic inline cathode ray tube washing machine situated in a corner 10 of a factory, thereby utilizing a minimum of oor area in an area otherwise considered nonproductive. An overhead chain conveyer 1l is supported from overhead supports in a conventional manner by means not illustrated. Chain conveyer 11 is moved in a single direction by means of a chain drive 12 which is located on the tracks through which the chain conveyer 11 moves. Chain drive 12 is illustrated more fully in FIG. 4 and is constructed in suchl a fashion that chain conveyer 11 is moved intermittently at a nonlinear, or varying rate that imparts substantially zero acceleration at zero speed, thereby preventing oscillations which normally result from starting and stopping. The time between moves depends on the length of time necessary for each cleaning cycle which takes place at each cleaning station. Cleaning stations 13, 14 and 15 are preferably located equal distances from each other, which distances, if made the same as the distance between hanging tubes located on chain 11, will produce maximum speed consistent with optimum results. ln operation, tubes are loaded on suitable tube carriers at a point not illustrated in FIG. 1, which tube carriers are supported from conveyer chain 11. As chain 11 moves, any single carrier will arrive first at a hanger position 16, which position is so chosen that the hanger will close a switch 17 located at said position in order to signify that the tube carriers are in synchronism with chain drive 12. The tube carrier then progresses from hanger'position 16 to cleaning station 13, at which time chain assembly 11 again stops. This action places the next tube carrier at hanger position 16 and the first carrier at station 13. Upon completion of the cleaning cycle at station 13 the chain drive 12 is again energized, thereby moving chain conveyer 11 to the next station which places the first carrier at cleaning station 14, the second carrier at cleaning station 13 and a new third carrier at hanger position 16. During the waiting time when chain conveyer 11 is not moving, chain lock 1S positively locks said chain conveyer 11 until completion of the cleaning cycles. FIG. 3 illustrates chain conveyer 11 constructed of a plurality of links l@ and a plunger 20 extending between a pair of said links 19, thereby positively and effectively preventing movement of said chain conveyer 11 during the waiting time. Plunger 20 controls switch 20a in such a manner that, when said plunger 20 is fully extended, switch Ztla opens, thereby preventing accidental starting of chain drive 12. Upon completion of the cleaning cycle of cleaning stations 13 and 14, plunger 20 is retracted, switch 20a closes, chain drive 12 is again energized, and the first tube hanger is moved to the next cleaning station 15, which thereby places the second hanger at station 14, the third hanger at station 13, and new fourth hanger at hanger position 16. The process then completes over and over again completely, automatically, and unattended. The switch and operating arms 21, 22 and 23 located` in cleaning stations 13, 14, and 15, respectively, serve the dual purpose of damping out any oscillations or movements in the tube hanger and, also, detecting the presence or absence of a cathode ray tube in said tube hanger. If a carrier is detected not carrying a tube, the microfor locking switch associated with that station will simply prevent said station from going through a cleaning cycleI Referring now to FIG. 2, there is shown a tube carrier 24 supported from chain conveyer 11 by means of a pivotal member 25. Carrier 24 is illustrated as being in hanger position 16, thereby closing microswitch 17, which indicates that chain conveyor 11 is in step with chain drive 12. Carrier 24 is preferably constructed of steel tubing having a relatively thick rubber cover, thereby effectively protecting tube 26, which is nested within the confines of carrier 24. The novel feature of carrier 24 is that said carrier is constructed symmetrically with respect to a line through the'center support 25 extending through the center of the supported cathode lray tube` 26. In order to support the neck of tube 26, a circular extension 27, through which the neck of tube 26 may be inserted, is made part of the carrier. This circular extension 27 has the dual purpose of supporting what is considered one of the weakest parts of the cathode ray tube, and also due to the added weight of said extension, more weight is placed at the lowest point from chain conveyer 11, thereby allowing carrier 24 to be moved with a minimum of oscillations in the direction of movement. FIG. 2 also illustrates a carrier 2S holding a cathode ray tube 29 in the rst cleaning station 13. As mentioned previously, with tube carrier 24 assumed in hanger position 16 then carrier 28 will be in cleaning station 13, chain drive 12 Will be inoperative, and plunger 20 of chain lock 18 will have extended, thereby positively locking chain conveyer 11. Since tube 29 is located in hanger 2S, switch 21 will be operated, thereby allowing the cleaning cycle for cleaning station 13 to operate. In addition to switch 21 indicating the presence of tube 29, the operating arm on said switch 21 serves the purpose of damping out even the smallest oscillations imparted to hanger 28. With the presence of cathode ray tube 29 determined, piston 30, from piston control solenoid 31 is inserted through the open neck end of cathode ray tube 29. With piston 30 fully extended, as indicated by the closing of upper limit switch 32, acid is pumped from the acid tank 33 by pump 35a through piston 36 and out nozzle 34 located at the end of piston 30. Nozzle 34 is preferably constructed without sharp edges or corners, thereby allowing a limited mechanical error in aligning the neck of the tube with the plunger. Since carrier 28 is pivotally connected to chain conveyer 11, a limited amount of camming action for aligning is tolerated. Nozzle 34 has a directional orifice, the opening of which depends upon which internal area of the tube is to be cleaned. For example, it was found desirable in station 13 to direct the acid at the phosphor-containing area of tube 29, whereas in cleaning station 14 the nozzle opening was altered, thereby directing the acid at the inside high voltage terminal. It can therefore now be appreciated that any number f cleaning stations may be used, and further, since the nozzle which ejects the cleaning acid is placed in close proximity to the interior portion of the tube being cleaned, lesser amounts of acid are needed, and further, a higher degree of cleaning is now attainable, since all prior devices usually inject the acid in a stream from outside the neck of the tube. One of the main advantages of being able to insert the nozzle within the tube is that the clean acid emanating from said nozzle is not contaminated by old acid leaving the tube. This is due to the nozzle being higher in the neck than the tube. The used acid ows down the side of the tube, down the neck into a suitable catch basin from where it is returned to tank 33. In the preferred embodiment cleaning station is not an acid-handling station but rather handles caustic soda in solution for arresting the action of the acid used in stations 13 and 14. Further stations using demineralized water may be added if necessary.

Upon completion of the cleaning cycle in cleaning station 13, piston 30 is fully retracted within piston control solenoid 31, which condition is indicated by a projection 0n piston 30 closing normally opened lower-limit switch 35. Since all the cleaning stations are constructed similar to that illustrated for cleaning station 13, the closing of all associated lower limit switches by the lowering of the respective pistons will indicate the end of all 'cleaning cycles for all cleaning stations, thereby deenergizing acid pump 35a, chain lock 18, and energizing chain drive 12.

Referring now to FIG. 4, there is illustrated chain drive 12 mounted on the same supports that hold chain conveyer 11. Chain drive 12 consists of a motor 36 driving a speed reducer 37 by means of a belt 3S. Speed reducer 37 servese the dual purpose of not only gearing down the speed of motor 36, but also of changing the direction of motion degrees, thereby allowing motor 36 to be mounted by suitable means in any convenient position above chain conveyer 11. The output of speed reducer 37 is obtained at shaft 39 in the form of a rotating force which is transmitted through arm 4% which is ixedly attached at one end to shaft 39. Arm 40 is pivotally connected at the other end to arm 42 by means of rotating pivot 41. The other end of arm 42 is restricted by means of a dolly assembly 43 that rides on the same track which supports chain conveyer 11. Dolly assembly 43 consists of the necessary bearings to maintain free and easy operation, and, also, a keeper 44 that engages and drives the links 19 of chain conveyor 11. Keeper 44 has freedom of movement in one direction only; therefore, as shaft 39 of speed reducer 37 rotates, arm 42, which is illustrated at the end of a power stroke or in its furthest position for forward travel, will begin to move in a direction opposite to the desired motion of chain belt 11, and, in so doing, keeper 44 will slide over links 19 without imparting any motion to chain conveyer 11. Upon completion of the cycle of shaft 39, arm 42 will begin travelling in the desired direction of motion of chain conveyer belt 11. but since keeper 44 is restrained, motion will be imparted directly to the chain conveyer belt 11 through links 19. Pivot 41, illustrated at the limit of the power stroke, closes a normally-open switch 45 that indicates the stopping of chain conveyer 11 and allows the cleaning cycles in the various cleaning stations to begin. At this point chain conveyer V11 is at rest, but motor 36 is still free to operate. Motor 36 will stop at a point just prior to the beginning of a new power stroke, when pivot 41 opens normally closed switch 45a. It can be seen, therefore, that chain drive 12 accomplishes a threefold purpose which is: (l) driving the chain belt 11 in a single direction only; (2) driving said chain belt in a predetermined intermittent, or stop-and-go motion, which stop periods are synchronized with the time necessary for each cleaning station to complete a cleaning cycle; and (3) chain conveyer 11 is driven at a varying or non linear speed, which is such that there is a minimum of acceleration at the beginning andl deceleration at the end of the driving stroke of chain conveyer 11, thereby practically eliminating any oscillating motion of the cathode ray tube carriers. The apparatus described in FlG. 4 imparts a sine wave motion to the chain drive 11, but it should be appreciated that other suitable driving systems, having the necessary requirements of imparting intermittent motions and, also, of driving said chain conveyer system at a nonlinear speed, may be used.

Referring now to FIG. 5, there is shown by way of example only, a schematic diagram for automatically controlling and operating the in-line bulb washing machine illustrated in FIG. 1. The basic requirements of controlling this system are that the position of the cathode ray tube carriers always be tested to be certain they are in synchronisrn with the chain drive, and further, that said chain drive does not operate until all cleaning cycles -for all stations are completed with their respective pistons fully retracted in their lowered position. It is necessary,

therefore, that the controlling system be responsive to the actions of all cleaning stations, rather than having a preset time schedule controlling the system irrespective of the individual requirements of each cleaning station. This concept, which basically comprises a continuous feedback circuit, will be explained further as the description of the circuit progresses. The following description will assume the system to be at rest awaiting the washing cycle. Before the washing cycle can begin, it would have bee necessary for switch 45, which closes at the end of the power stroke, to have been closed. This is necessary in order to signify that chain conveyer l1 is at rest. Before the cleaning sequence can begin, another test is necessary, which is that the tube carriers be in synchronism with chain drive l2. This will be indicated by the closing of switch i7, which is in the hanger position 16. With switches i5 and 17 closed, a path from one side of the line 46 is presented through switch 45 and through switch i7 to a timer and control 47, which, in turn, is connected to the other side 43, thereby completing the circuit to timer and control 47. Associated with timer and control 47 is a single-pole double-throw switch, having operatin" arm 49 normally closed against terminal 50, and capable of being transferred to terminal 51 after a controlled delay by means of timer and control 47. Switch 17 is electrically connected to operating arm 49 and, also, to operating arm 52 of a single-pole doublethrow switch operated and controlled by timer-and-control 53. Operating arm 52 is normally closed against terminal 54 and is capable of being transferred to terminal 55 in a similar manner as the switch associated with the timer-and-control 47. Both timer and control 47 and 53 are of the type that begin their sequence with power applied, and automatically reset themselves when power is removed. Terminal '4 is, in turn, connected to a holding coil S6, which thereby closes operating arm 57 against terminal SS. Terminal 57, in turn, is connected to line 46 before switch 45, thereby placin(Y a hold on the circuit, previously described, through switch 17, which circuit is now independent of the opening or closing of microswitch e5. The circuit from terminal 54 is also connected to chain lock 1S which controls plunger 2G. Switch 6G is mechanically linked with plunger 20 in such a way that, whenever said solenoid is energized, which has the effect of locking chain conveyor belt 1l, switch 69 is opened. Another path from terminal 54 is connected to switch 2i, the closing of which indicates the presence of a cathode ray tube in cleaning station 13. Similar circuits from terminal 54 are connected to switch 22 and 23 of cleaning stations i4 and 15 for the same reasons as described for cleaninU station 13. By assuming a cathode ray tube at cleaning station 13, switch 21 will be closed, which thereby completes the circuit from line 45 through operating arm 57 to terminal 5S, through switch 17, to operating arm 49 through operating arm S2 to terminal 54 through switch 2l through piston control solenoid S and hence back to the other side of the line 4S. Energizing piston control solenoid 3l will cause piston 30 to move upward into the neck end of the cathode ray tube to be cleaned. Piston 30, shown being fully extended, will trip a mechanical linkage, thereby closing upper limit switch 32. The closing of switch 32 will energize pump 35a through the circuit beginning with line 46 through operating arm 57 to Contact S8 through switch 17 through operating arm 49 to terminal S0 through switch 32 through pump 35a and back to the other side of the line 48. With pump 35a energized, suitable cleaning fluid or acid will be pumped from tank 33 through piston Si) and out the nozzle 34 into the tube to be cleaned. Cleaning stations l@ and l5 are connected in a similar manner as those just described for cleaning station 13.

The length of the wash cycle is determined by the time setting of timer and control 47. After a suitable time, timer and control 47 causes operating arm 49 to transfer from terminal 50 to terminal S1, thereby energizing timer and control 53 and also cle-energizing the circuit to pump 35a associated with cleaning station i3, and also all other pumps associated with all other cleaning stations, thereby stopping the pumping of all cleaning fluid. After a suitable time, calculated to allow the pump motor to stop and for the cleaning fluid to leave the lines, timer and control 53 operate, causing operating arm 52 to transfer from terminal 54 to terminal 55. Transferring of operating arm 52 de-energizes holding coil solenoid 56, chain locks piston control cylinder 31 associated with cleaning station i3, and all other similar solenoids associated with cleaning stations 14 and 1S. When chain lock 18 deenergizes, plunger Ztl is retracted from chain conveyer l1, thereby closing switch 26a. De-energizing holding coil 56 will move operating arm 57 from contact with terminal 58, and since switch 45 has been opened by the movement of pivot 41 at the beginning of a new power stroke, the electrical circuit through switch 17 is opened, which now de-energizes timer and control 47, allowing said timer to be reset, which, in turn, will transfer operating arm 49 back to normally-closed contact 50. Transferring of operating arm 49 will disconnect timer and control S3, which has a similar effect in resetting said timer and transferring its associated operatingarm 52. back to normally-closed contact 54. A further effect of de-energizing timer and control 4'7 by the de-energizing of holding solenoid 56, is the de-energizing of piston control solenoid 3i, thereby allowing piston 3@ to be returned to its normal position` ln a similar manner the pistons of all associated cleaning stations will be similarly retracted. Piston 3i), when fully retracted, will close lower limit Switch 35, as in a similar manner the retracting of the associated pistons for stations 14 and 15 will close their associated lower limit switches 62 and 63. With the motor in a stopped position awaiting the end of the cleaning cycles for each ceaning station, pivot di on chain drive 12 will be in the rear position preparatory to delivering a power stroke to drive chain conveyer 11. In this position pivot 41 will also be holding open normally closed switch 45a. In this position control for the starting of motor 36 is determined by lower limit switches 3S, 62, and 63 and also the dropping out of chain lock 18 which places safety switch 6ft in a closed position. Under these stated conditions control motor 36 will again operate, driving operating arm 42, which, in turn, will move chain conveyer 1l to a new power stroke position. The limit of the power stroke is indicated by pivot 4l closing normally open switch 4S. Assuming a tube hanger in the hanger position, normally open switch 17 will also be closed, thereby beginning the cleaning cycle previously mentioned. At this time the chain conveyer is at rest and solenoid 59 is energized, which has the effect of locking said chain conveyer, as previously mentioned, but motor 36 is not stopped, and in fact is free to rotate and does so, driving operating arm i2 back until normally closed switch 45a is opened. lt is the opening of switch 64 that actually stops motor 36. This method of stopping motor 36 saves time in the total operation of the conveyer belt, since operating arm t2 can be returned to a position just prior to a power stroke, while the cleaning operation progresses. The only timing requirement in the system is that when pivot 4l closes normally open switch 45, holding solenoid 56 should be closed and operating arm 57 (the holding contact) operate and close before operating arm 42 allows normally open switch 45 to open.

This completes the description of the embodiment of the invention illustrated herein. However, many modi-- iications and advantages thereof will be apparent to persons skilled in the art without departing from the spirit and scope of this invention. Accordingly, it is desired that this invention not be limited to the particular details of the embodiment disclosed herein except as defined by the appended claims.

What is claimed is:

l. In combination, a movable conveyer system, moving means for intermittently moving said conveyer system at a varying rate, a plurality of tube-holding means each adapted to hold a cathode ray tube, attaching means for suspending each of said tube-holding means from said conveyer system, said moving means being responsive to a predetermined positioning of said tube-holding means for maintaining synchronism between the position of said tube-holding means and said moving means and driving said conveyer system and hence said tube-holding means at a varying rate that imparts substantially zero acceleration at zero speed thereby preventing oscillations of said tube-holding means which normally result from starting and stopping, said moving means propelling said tubeholding means through a station at which process means is located, and means for stopping said conveyer system when said tube-holding means is at said station.

2. In combination, a movable conveyer system, moving means for intermittently moving said conveyer system at a. varying rate, a plurality of tube-hoiding means each adapted to hold a cathode ray tube, attaching means for suspending each of said tube-holding means from said conveyor system, said moving means being responsive to a predetermined positioning of said tube-holding means for maintaining synchronism between the position of said tube-holding means and said moving means and driving said conveyer system and hence said tube-holding means at a varying rate that imparts substantially zero acceleration at Zero speed thereby preventing oscillations of said tube-holding means which normally result from starting and stopping, said tube-holding means comprising a circular extension adapted to receive the neck of a cathode ray tube and tube-supporting means connecting said circular extension and being symmetrical about a line passing through said circular extension and said attaching means, said moving means propelling said tubeholding means through a station at which processing means is located,

and means for stopping said conveyer system when said tube-holding means is at said station.

3. ln combination, a movable conveyer system, moving means for intermittently moving said conveyer system in a single direction, a plurality of tube-holding means each adapted to hold a cathode ray tube, attaching means for suspending each of said tube-holding means from said conveyer system, said moving means being responsive to a predetermined positioning of said tube-holding means for maintaining synchronism between the position of said tube-holding means and said moving means and driving said conveyer system and hence said tube-holding means at a varying rate that imparts substantially zero acceleration at zero speed thereby preventing oscillations of said tube-loading means which normally result from starting and stopping, said tube-holding means comprising a circular extension adapted to receive the neck of a cathode ray tube and tube-supporting means connecting said circular extension and being symmetrical about a line passing through said circular extension and said attaching means, a plurality of stations at which process means are located, said moving means propelling said tube-holding means through said stations, means for stopping said conveyer system when said tube-holding means are at said stations, and means for positively preventing said conveyei system from moving during the processing of said tubes at said stations. Y

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